The present invention relates to a replenishable ink cartridge for use in an ink-jet printer with a recording head.
A prior art ink jet printer in which an ink-containing unit and an ink jet recording head are mounted on a carriage is disclosed in European Patent Publication No. 581,531. In the disclosed printer, to prevent printing failures caused by fluctuation of ink head pressure or air bubbles due to movement of the ink cartridge caused by the movement of the carriage, the ink container is divided into two regions. A first region of the container adjacent the recording head houses ink impregnated in a porous member, and a second region contains liquid ink without a porous member. This structure enables the ink to be conducted to the recording head via the porous member so that the problems arising from movement of the ink in the cartridge are prevented from occurring to a certain extent.
As shown in FIGS. 8 and 9, to cause the ink absorbed in a porous member 451 to flow into the recording head (not shown) smoothly, a projecting member 452 is formed inside a container body 440 so as to draw ink toward an ink supply inlet 458 of an ink supply port 450 by locally pressing porous member 451 to selectively increase the capillary force.
To improve full-color print quality, on the other hand, an ink-jet recording apparatus has been designed to reduce the granular look of printed material produced by printers of the prior art by using light ink and dark ink to form dots. Such a recording apparatus requires ink of at least six colors: dark magenta, light magenta, dark cyan, light cyan, yellow and black. One problem caused by using an increased number of inks, however, is that the weight of the carriage is increased, which thereby impairs the movement of the carriage and increases the time it takes the carriage to return to a printing position.
To mitigate the aforementioned problems, the weight of the carriage is reduced by decreasing the size of each color's ink cartridge. Consequently, the width of each color in a container body forming the ink cartridge is narrowed to a small dimension. Referring to FIG. 9, as the width of the ink cartridge is narrowed, however, the rigidity of porous member 451 correspondingly increases and a portion 459 of porous member 451 located between a front wall 456 and projecting member 452 is deformed into a V shape, thereby creating a blank space 454. A portion 460 located between projecting member 452 and a back wall 461 creases such that portion 460 is not pressed against projecting member 452, thereby creating a blank space 455. Finally, as is shown in FIG. 8, at a location above projecting member 452, porous member 451 spans the gap from projecting member 452 to a side wall 463 and an internal wall 464, thereby creating a blank spaces 453. Thus, blank spaces 453, 454, 455 are produced because porous member 451 does not fully occupy the space defined by container body 440. Even though spaces 453, 454, 455 may be filled with ink, because spaces 453, 454 and 455 are positioned below ink supply inlet 458, ink stored in such spaces cannot flow to the recording head via ink supply port 480. Thus, spaces 453, 454, 455 waste the ink and also may become bubble reservoirs.
One possible solution to this problem is to join porous member 451 to container body 440 during the manufacturing process. However, to do so requires that porous member 451 be cut to precise specifications, which is a complicated undertaking. Moreover, the supply of ink from those portions of porous material that would occupy spaces 453, 454, 455 in such a construction would be reduced because the portions would not be adequately compressed if joined to the walls of container body 440.
Accordingly, it is desirable to provide an improved ink cartridge that overcomes the drawbacks of the prior art.